The American birth rate took another dive, to 60.2 births per thousand women between ages 15 and 44, a sharp drop from 62.0 at the end of 2016, and an even more dramatic decline since the pre-recession peak in 2007 of 69.3. There were an estimated 3.85 million live births in 2017. The last time we had fewer total live births in America was 30 years ago, in 1987 — when the American population was only three-quarters as large as it is today.

So what happened? Has something gone suddenly wrong with American culture or the American economy? Perhaps. But the more likely explanation is that America is simply reverting to the mean of other industrialized nations. Indeed, American fertility may have been less of an outlier among that group than it seemed for years now. And if that's the case, then it suggests that solutions aren't likely to be found in nostalgia for America's more fertile past.

To explain how that could be, it's worth examining the data a little more closely. Along with the drop in live births, America's Total Fertility Rate (TFR) — a prediction of how many children the average woman will have in her lifetime — has dropped to a new low of 1.76, approaching the all-time low of 1.74 children per woman reached in 1976. But the TFR bases future predictions on current fertility patterns. Baby booms and busts alike attest to the fact that these patterns are quite changeable, which can throw predictions distinctly out of whack.

For instance, America's TFR at the height of the 1950s baby boom was over 3.5 children per woman, meaning that, at the time, demographers predicted that the average woman would bear 3.5 children. But in fact, the average family size during the baby boom was under three children. Why the error? Women in the 1950s married and had children earlier than in previous decades, so when demographers predicted future births based on the experience of women from previous decades, they failed to predict that these young brides would also stop having children at a younger age, precisely because they started earlier. Family sizes did grow, but not by as much as expected. The opposite effect was observed decades later, as women delayed childbearing into their 30s, resulting in TFRs that underestimated true fertility.

Something similar may have happened during the more modest baby boom of the 2000s.

The late 1990s and 2000s was a period of high immigration, particularly from Latin America. These immigrants were more likely to have children soon after arriving, regardless of their age upon arrival, likely reflecting some combination of pent-up demand for childbirth and an improvement in economic circumstances. That boosted the TFR of immigrant mothers. But their subsequent fertility didn't keep up with predictions. In fact, over the past decade, the TFR for Americans of Hispanic origin has dropped far further and more rapidly than that of non-Hispanic whites, African Americans, or Asian Americans. Some of that may reflect acculturation or economic hardship, but a large percentage of this drop may merely reflect a prior overestimate of lifetime fertility, driven by the timing of childbearing among recent immigrants.

If so, then America's overall TFR — which was above replacement in the 2000s — may have been inflated as well. Rather than something having suddenly gone wrong, things may never have been quite as right as we thought.

The data show other ways in which things might not have been as right as we thought. A key component to family formation is having room for your family to live and grow. During the 2000s, housing prices rose dramatically — but housing costs actually dropped, as interest rates plummeted, lending standards loosened, and minimal downpayments were required. All of this came to an end with the bursting of the housing bubble and the subsequent financial crisis, but while it lasted it made it more possible for people to start families during a period of sluggish employment growth. So it's probably not an accident that the drop in fertility over the past decade has been most pronounced in Western states where the housing bubble was most severe and the subsequent crash most pronounced.

All of these factors suggest America's declining fertility rate is more of a reversion to the mean than a sudden shift.

It suggests that America isn't as exceptional as it likes to think. Even after the recent decline, America's TFR doesn't look that different from comparable Western countries. It's about the same as the U.K., somewhere between Canada and France. In general, the only countries that have consistently high fertility are those with low levels of development — specifically, low rates of urbanization and low rates of female literacy. Developed countries generally struggle to maintain fertility close to replacement level, and the exceptions — like Israel — are in many ways sui generis.

What about culture? Those with the most persistent concerns about low fertility point to deep cultural changes as both the cause and consequence of low fertility — a waning of religiosity and a "spirit of decadence" that leads to a lack of concern for the future. Indeed, they sometimes point to Israel as a counter-example of a modern country with a high level of religious observance and a strong sense of communal purpose, and credit those factors for its rising fertility. If these factors are dispositive, though, how to explain that Iran's TFR is now well below replacement, or that Saudi Arabia's is falling rapidly toward that level? How to explain that Poland, arguably the European country with the strongest Catholic devotion and a very high level of national pride, is struggling to get its TFR up from a miserable 1.35, far below that of the decadent Netherlands?

Culture surely matters, but the dramatic decline in fertility is cross-cultural, and the developed countries that have done the best job of maintaining replacement-level fertility or close to it are those that have worked hardest to make family-formation practical in a modern context rather than fighting modernity. They've made employment family-friendly, and particularly mother-friendly. They provide generous child-care support and free education, and have adopted policies to bring down the cost of housing. France is the standout among European countries in terms of results, but the BeNeLux and Scandinavian countries have also sustained higher fertility rates than many other European countries by similar means. (It's worth noting that Israel follows many of these policies as well.)

These kinds of policies are not irrelevant to the American situation. America's workplace is exceptionally hostile to parenting — and gets only more hostile the further down the education and income scale you go. And growth in our economy is increasingly concentrated in coastal urban centers where housing costs are a real barrier to family formation.

America saw itself for a long time as an exceptional country — a more religious country, with a stronger sense of national purpose, a more dynamic economic system, and room to breathe. And it's tempting to think that the key to recovering — or even stabilizing — is to recover lost virtues. We had a baby boom in the 1950s, didn't we?

But if we aren't as exceptional as we thought, then it's time to stop looking backward for fixes, and time to start looking forward.